Apparatus for drying timber and other moisture-bearing substances.



H. D. TIEMANN. APPARATUS FOR DRYING TIMBERAND OTHER MOISTURE BEABINQ QUHBTANOES APPLICATION run an. 15 1319 QUINN.

Patented Ma I may be used by the Government of the' HARRY D. TIEMANN, OF WASHINGTON, DISTRICT OF COLUMBIA.

APPARATUS FOR DRYING TIMBER AND OTHER MOISTURE-BEARING SUBSTANCES.

Specification of Letters Patent.

Application filed March 15, 1910. Serial No. 549,572.

(DEDICATED TO THE PUBLIC.)

To all'whom it may concern:

Be it known that I, HARRY D. Trmmxn, a citizen of the United States, and an employee of the Forest Service, United States Department of Agriculture. :1 legal resident of the District of Columbia, residing at the city of Washington therein, (whose post-- oflice address is 1714 Q street,) have invented new and useful Improvements in Apparatus for-Drying. Timber and other Moisture-Bearing Substances, and have made application, by petition of even date herewith, under the act of March 3, 1883, chapter 143, (22 Stat., 625,) praying that Letters Patent therefor may be granted to me.

The invention herein described and claimed United States or by any of its officers or employees'in the prosecution ofwork for the United States, or by any person in the United States, without payment of any royalty thereon.

The following is the specification of the invention: I

My invention relates to an improvement incurrents of air, thereby increasing the local circulation and condensing the moisture therefrom, is well known. For this purpose the warm moist air is brought in contact with condensing surfaces, usually of metal, placed in an auxiliary passageway or chamber. The main diificulty with such condensing kilns is the erosion of the metal surfaces by the artificial moisture from the wood. What I claim'in my invention as original and an improvement is the elimination of the metal surfaces by the direct use of water and also the doing away with the auxiliary chamber, by conducting the whole operation within the main drying chamber. To accomplish this result it is only necessary to have a kiln of the simplest type of construction, consisting essentially of a rectangular chamber having walls preferably of hollow tile or cement construction, a track upon which the truck full of lumber is runin, and

a with suflicient space beneath the trackfor the heating pipes or other means of heating. The nature, characteristic features and scope of my invention will be readily understood by the following description taken in connection with the accompanying drawings, wherein Figure 1, is a cross section of. a drying chamber showing water trickling'or flowing down the side walls thereof; and Fig. 2 is a side elevation of the kiln.

Referring to the drawings, L re resents the pile of lumber to be dried, anc P the heating pipes.

' N indicates an unobstructed space between the lumber and the walls, sufficient'to allow of a free passage of air. Arranged close to the end walls of. said chamber or adapted to enter therethrough are water pipes, S S. These pipes, S S, are employed for direct ing a spray of water, W 7, against the side walls. The water trickles or flows down the side walls into a trough, T, at the bottom, by which it is conducted out of the kiln. I

M M designate baflle plates arranged to prevent counter currents of air and so to assist-the natural circulation, and R indicates the exhaust chimney as shown in Fig. 2 of the drawings.

The operation is as follows: The heated air rises through the lumber as indicated by the arrows, taking on moisture and therefore becoming lighter as it rises. As it comes in contact with the side walls it is cooled by the spray of cool water and at the 'same time deprived of a certain amount of its moisture by condensation upon thewater. A downward current of dry air therefore takes place close to the walls.

-In beginning the drying operation in some cases, as with green lumber for instance, it may be necessary to hu'midify the upward current of air. by supplying free steam directly to the air, or by, bringing the air in contact with heated water before it reaches the lumber. This arrangement is applicable to either the. progresslve type of kiln or to the stationary type.- In t e progressive type, which consists in one or more long tunnel-like chambersin which the undried lumber isrun into one end on trucks, progressively movedalong as it dries, and finally taken out at the dry end, it is desirable to have an exhaust chimney, as

Patented Mar. 5, 1912.

' sl iown in 'Fig. -2',at the charging or moist end, in orderto create a suflicient current of air lengthwise of the chamber toward the moist end'- to holdthc moisture at that end and secure aproper graduation of humidity from one end of the kiln to the other.

Otherwise, the Water condensers-at the dry fend wouldibe oalledfupon toremove an unilue. quantity of moisture detrimental to the economic working. 3 p

While I'have shown in the drawings the application of this principle to one type "of kiln, I do not restrict myself to use with any specific type of drying apparatus, as itis manifestithat it is applicable to many others.

vTo supply the .necessar heat required to evaporate thefmoisture f era the lumber requires an enormous c rculatlon of air, on aecount offits small specific heat, and this circulation is necessarily chiefly an internal local one requiring more air thancan be supplied from without except by strong forced draft. Good drying depends upon a unif rm-and suflicient supply of heat given i by the circulating air to maintain the internal temperature of the 'WOOd and at the same time a control of the rate of the surface evaporation by the proper humidity of the circulating air. My. improvement ""a ,proachesthese ideal conditions more nearly than any existing drying apparatus oi stantially as shown.

which Tam aiva1;e,'and in addition 'econo nnzcs the heat; as the same air is used re- .peatedly without being cooled to any great extent.

In a kiln, comprising a drying chamber providedwith heating pipes and pipes for admitting free steam, ba fllc plates suitably arranged for preventing counter currents of air within said chamber, anexhaust chimher for creating a current of air -lengthwis'e 'oi'2ill0 chamber, a series of perforated water )i )OS arranged, to enter throu 'h the end 1 l. 1-

wallsof said-chamber.and supply water to the side walls at. a temperature less than that of the air, a trough at the bottom of I-Ia\-'ing..thus described my invention, I- claim as follows:

Lfigncd at Washington, D. (3., this eleventh day of. March, 1916; s Y.

' HARRY-D.1;TIEMANN. Witnesses: v

' Tnonms G. SIIEARMAN,

R. N. HILL-lets, J r. 

